Fix linux wheel build versioning information.

New release (ParallelSSH#68)

Disabled OSX 10.11 wheel builds
Updated travis cfg for osx builds
Removed system package builds. Updated travis cfg to not login or push to docker on PR builds.
Switched testing to pytest.
Removed channel close on channel object de-allocation. Removed GIL release on session and channel object de-allocation. Updated Changelog.
Removed out of repo package files before building wheels and updated gitignore - resolves ParallelSSH#14
Migrated manylinux wheel builds to openssl 1.1.
Migrated Windows builds to openssl 1.1.
Updated changelog. Updated manylinux wheel embedded libssh2 version.

Updated appveyor cfg. Added openssl and zlib static archives for wind…

…ows builds.

Added libssh2 modules to package data. Resolves ParallelSSH#51.

Added python 3.7 target to travis cfg. Removed OSX 6.4 builds from travis cfg - deprecated by travis-ci.
Updated changelog.

Added libssh2 modules to package data. Resolves ParallelSSH#51.

Added python 3.7 target to travis cfg. Removed OSX 6.4 builds from travis cfg - deprecated by travis-ci.
Updated changelog.

Handle EAGAIN for channel and sftp writes correctly and return rc, by…

…tes_written tuple so clients can resume from last written byte on next call to write.

Updated docstrings for channel write functions, tests, travis cfg, flake8 configuration for sftp.

Updated readme, installation instructions in documentation.

Updated setup.py for readthedocs builds.
Updated travis cfg.
Updated PyPi classifiers.

Merged and updated OSX travis configuration.

Updated travis cfg

Updated travis cfg